In an environment for centralized management of desktops, multiple client machines may receive access to or execute a computing environment based on copies of a single “golden master” desktop disk image. A machine disk image or desktop disk image may be an image of an operating system (OS), and may include sets of applications and customizations representing a working environment for a user. In some environments, a machine image includes files used to execute a virtual machine (VM) that then executes an operating system or other user applications. In other environments, a desktop image includes files used to execute an operating system or other user application, and either a physical machine or a virtual machine may execute the desktop image. An image of a machine or desktop may be generally referred to as a base disk image.
One aspect of desktop administration is the need to apply changes to either the operating system or to installed applications within the desktop environment (e.g., to perform upgrades or other maintenance). Users on remote clients may create, in effect, their own independent machine image. For example, a change requested by a user to a base disk image is stored in a delta file associated with that user. The combination of the base disk image and one or more delta files associated with that user is referred to as the user's machine disk image. In another example, machine disk images are patched individually. This may be expensive in terms of time taken, as typically each machine is booted, patched and then shut down and re-started. Additionally, this may be expensive in terms of disk usage, as patching will lead to changes in the individual delta files, rather than to changes in the common base disk image. In these examples, changes due to a patch are typically applied to the delta files rather than the base disk image, thus ballooning the size of the delta images and increasing storage requirements for the delta files.